The present disclosure relates to a solid-state mass memory storage device. More particularly, the disclosure relates to a semiconductor mass memory storage device suitable for disk drive replacement.
As the volume of data generated by computing devices increases, the importance of memory space rises. Over the past several years, increases in demand for memory has caused a concomitant increase in the capacity of mass memory storage devices. Conventionally, these mass memory storage devices comprise rotating mass storage devices such as disk drives. Although great strides have been made in disk drive design in terms of capacity and speed, the versatility of conventional disk drives is limited. As a first matter, disk drive technology could soon reach a limit imposed by the superparamagnetic effect (SPE). As is known in the art, SPE is a physical phenomenon in which the energy that holds the magnetic spin in the atoms forming each bit becomes susceptible to ambient thermal energy and, therefore, is subject to random flipping which corrupts the data which the atoms represent. Unfortunately, the miniaturization currently popular in disk drive manufacture exacerbates the SPE problem.
A second limitation of disk drives relates to speed. Because disk drives require moving parts, the speed at which data can be stored on or accessed from the drive is limited by the speed with which the various mechanical parts of the drive can move. To increase this speed, manufacturers have continually increased the speeds at which the internal disks of the drives rotate. However, along with this increased angular velocity comes increased air turbulence and vibration which can cause misregistration of the disk tracks. In addition, to achieve high capacity and high speed, disk drives must be very precise in operation. Typically, disk drives comprise one or more disk platters and a plurality of read-write heads which record and retrieve data from circumferential tracks formed in the platters. The heads are normally moved with servomechanical actuator arms. In order to properly satisfy their record/write functions, the heads must be positioned in very close proximity to the platters, the separation between the heads and the platters typically measuring only fractions of microinches. This level of precision often results in a very fragile mechanism that can be easily damaged by moderate to large vibrations. Such susceptibility is particularly disadvantageous for portable computing devices which are often bumped and/or jolted through normal use.
In addition to fragility, disk drives further present the disadvantage of requiring relatively large amounts of power to operate. This again relates to the fact that disk drives have moving parts which require electrical power. Although not a major concern for plug-in devices such as desktop computers, this power consumption can be problematic for portable devices.
Yet another disadvantage of conventional disk drives is the physical space normally required to house the drives. Again, space constraints normally are not critical for desktop devices. However, space typically is at a premium in portable devices where smaller is often considered better. Due to such space limitations, portable devices typically do not enjoy the redundancy possible with stationary devices such as conventional network servers. As is known in the art, such stationary devices normally include a redundant array of inexpensive disks (RAID) which share the data stored in the disk drive. With this arrangement, a failure of a particular disk will not necessarily adversely effect the data stored by the drive in that the data normally can be reconstructed due to the redundancy of the data stored across the several disks. Typically, the desired level of redundancy, e.g. RAID 5 protection, requires a minimum of three disks. Due to the space limitations of portable devices such as notebook computers, however, normally only one such disk is provided. Accordingly, the desired redundancy typically cannot be provided for such devices.
From the foregoing, it can be appreciated that it would be desirable to have a high capacity, high speed, mass memory storage device which uses relatively little power, which is relatively rugged in construction, and which provides for data storage redundancy.
The present disclosure relates to a solid-state mass memory storage device. The solid-state mass memory device comprises a printed circuit assembly and a plurality of nonvolatile, high density storage devices mounted to the printed circuit assembly and electrically connected thereto. The solid-state memory device includes at least one controller mounted to the printed circuit assembly and electrically connected thereto, and a connector mounted to the printed circuit assembly and electrically connected thereto, the connector being adapted to electrically connect the solid-state mass memory storage device to a separate electronic device.
In one embodiment, the printed circuit assembly has a form factor equivalent to a conventional disk drive and the at least one controller includes control electronics and firmware which emulate a disk drive such that the device in which said solid-state mass memory storage device will interpret and treat the solid-state mass memory storage device as a disk drive. With such an arrangement, the solid-state mass memory device can be used as a disk drive replacement.
In another embodiment, the high density storage devices are removably mounted in storage device sockets formed in said printed circuit assembly in a redundant array.